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Test Code M229 Influenza A Virus, Influenza B Virus, and Respiratory Syncytial Virus (RSV) Detection by PCR

Performing Laboratory

Barnes-Jewish Hospital Laboratory



Multiplex Real-time Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) using the Cepheid Xpert Xpress Flu/FSV assay performed on the GeneXpert System


Literature Reference: 

Package insert: Xpert Xpress® Flu/RSV – GeneXpert Package Insert.  Cepheid, Sunnyvale, CA.  301-2907 Rev. A, February 2017.

Specimen Requirements

Acceptable Specimens:1 nasopharyngeal (NP) swab in viral transport medium.


Collection Procedure:

Call Barnes-Jewish Hospital Laboratory Customer Service at 314-362-1470 to obtain Viral Transport Medium Collection Kit.


1. Collect specimen using wire shaft swab(s) provided.
2. Place swab(s) in vial, break or cut off shaft of swab(s), discard shaft, tightly cap tube.
3. Maintain sterility and forward promptly.

4. If transport is delayed, refrigerate specimen. Specimen cannot be frozen.

Note: Specimen source is required.

Day(s) Test Set Up




Sunday through Saturday
Cut-off time: During “non-season”:  Testing performed once per shift, 0600, 1000, 1800

During “active season”:  Testing performed every 4 hours.  

Turnaround Time:
STAT: not available

During “non-season”:  final report available by the end of the shift received.

During “active season”:  Results available within 4 hours.

Reference Values


Flu A target RNA not detected


Flu B target RNA not detected


RSV target RNA not detected

Test Classification and CPT Coding

Test Classification:

This test is performed using the Cepheid Xpert Flu/RSV Assay.  This is a multiplex, real-time reverse transcriptase PCR assay that detects influenza A, influenza B, and respiratory syncytial virus RNA.  This assay has been cleared by the US Food and Drug Administration, and its performance characteristics have been verified by the Barnes-Jewish Hospital Microbiology Laboratory.


CPT Code:




Additional Information

For BJH Laboratory Use Only
Minimum Volume:
1 NP swab in viral transport medium
Laboratory Processing Instructions:
Test performed in BJH Microbiology.

Specimen Transport Temperature

Ambient/Refrigerate OK/Frozen NO